No matter how forcefully we might withdraw from it, patronise it or destroy it, nature remains at the very heart of the human experience. This is the conviction expressed in Richard Mabey's enthralling meditation on life in East Anglia, which will infuse even the most jaded city dweller with a renewed sense of wonder at the natural world.

But withdraw from nature is precisely what, in 1999, the author did. An established nature writer, award-winning biographer and television producer, Mabey laboured for years over Flora Britannica, his encyclopaedic guide to the wild botany of this country. Following the book's completion and the death of his mother, he retreated into the Chilterns house that had been his home since birth. It became evident, when he could no longer venture into the woods and wildernesses that were the source not just of his occupation but of his profoundest pleasures, that Mabey was seriously depressed.

What, he is prompted to wonder here, is the natural function of depression? Nothing benefits from it, 'no opportunist virus or evolutionary climber. It seems to have no connection with the biological business of living at all.' This is the restless spirit of inquiry that characterises Mabey's writing and makes it hard to believe that, over a lengthy period, his interest in the outside world dwindled to nothing. It was only when he was prompted to leave the family home and move to East Anglia - and when he fell in love there - that his interests were revived.

The book traces his slow recovery in the Norfolk fens and, as testament to the success of his 'nature cure', it positively glows with deeply-felt love and enthusiasm for the wildlife around him - Konik horses, winter heliotropes and even the ancient moats and roads that enrich the landscape's 'narrative'. It also interrogates the seeming contradiction in nature writing: 'Isn't a life of words the very antithesis of a life of nature?'

Thankfully for us, Mabey came to terms with the contradiction. He has produced an incisive yet marvellously free-flowing exploration about what the natural world means to us in the 21st century.